docstr: Call this function in the main event loop.
  Similar to Twisted's ``callFromThread``.
docstr_tok: ["Call","this","function","in","the","main","event","loop",".","Similar","to","Twisted","'s","``","callFromThread","``","."]
code: def call_from_executor(self, callback, _max_postpone_until=None):
      """
      Call this function in the main event loop.
      Similar to Twisted's ``callFromThread``.
      """
      self.loop.call_soon_threadsafe(callback)
  
file_path: catboost/contrib/python/prompt-toolkit/py2/prompt_toolkit/eventloop/asyncio_posix.py
imports: from __future__ import unicode_literals
  from ..terminal.vt100_input import InputStream
  from .asyncio_base import AsyncioTimeout
  from .base import EventLoop, INPUT_TIMEOUT
  from .callbacks import EventLoopCallbacks
  from .posix_utils import PosixStdinReader
  import asyncio
  import signal
label_desc: Use image node_id 6 for calling the PosixAsyncioEventLoop obj's underlying member method code with example usage: obj.call_from_executor(callback, _max_postpone_until) without return types